The present invention relates to agricultural implements. More specifically the present invention relates to an apparatus and method for treating soil using microwave energy.
Agricultural crop production requires preparing a bed of soil prior to planting. The task of properly preparing the soil for planting includes treating the soil to preclude germination of existing seeds, killing weeds prior to sowing seed, and killing insects. To accomplish these preparatory tasks, many farmers use machinery to add chemical pesticides, herbicides and/or insecticide to treat the soil prior to sowing seed. These chemical additives are applied to provide the best possible growth medium for the crop. One problem with chemical additives is that chemicals can damage the environment, especially water supplies. Another problem with chemical additives is that rain can cause the chemicals to run off the field instead of penetrating downward into the soil which leaves some of the existing seeds, weeds, and insects alive to adversely affect crop yield.
Another method for treating soil includes administering heat to the soil. The heat is produced and distributed in various ways to heat the soil up to 80-90 degrees Celsius, which is sufficient to kill the majority of pests present. One specific heat based method employs boiling water to sterilize the soil. This method is expensive and generally only economically practicable under limited circumstances. One method that uses boiling water to sterilize soil is described in U.S. Pat. No. 5,622,123. This patent discloses the use of hot water with soil tilling for penetration, and an insulating foam layer which is placed on the soil surface to retain the heat from the water. In addition to being very expensive, hot water based treatments have many problems. One problem is that they require a mechanically complex apparatus to effect penetration and long hoses between the water heating element and the apparatus for penetrating application to the soil.
Another heat based method for preparing soil includes the use of microwave energy to heat the soil to the appropriate pest destruction temperature. Prior art devices that disclose the use of microwave energy are disclosed in U.S. Pat. Nos. 5,141,059 and 6,401,637, and U.S. patent application Ser. No. 10/245,787. The devices disclosed in these patents emit microwave radiation downward into the soil as they move over the top of the soil. One problem with these devices is that they do not adequately loosen the soil as they emit the microwave energy. Loosening the soil helps to thoroughly treat the soil with the radiation. Another problem with these devices is that it is difficult for the user to determine the depth that the soil being treated.
Therefore, there is a need for an improved farming device which minimizes negative environmental impact while increasing the efficiency and productivity of farming operations.